潜流人工湿地堵塞程度的原位测定研究

人工湿地因其生态友好、运行费用低廉、处理效果好而被广泛运用于污水处理中，然而潜流人工湿地在运行过程中会发生填料堵塞，导致其利用率下降、寿命缩短，但目前还缺乏简单有效的原位测定人工湿地堵塞程度的方法和仪器.为了客观地评价湿地的堵塞程度，以渗透系数法为测定原理构建了人工湿地堵塞程度原位测定法，结合压力探测和数据处理模块开发了人工湿地堵塞程度原位测定仪，并进行了实验室试验和原位测量以检验方法和仪器的可行性.实验室试验中测量了利用砂土和砾石模拟的不同程度的堵塞.结果表明:当填料砂土与砾石的质量比为2:1、4:1、8:1时，堵塞系数分别为0.69、0.84、0.91 km/d，测得的堵塞系数和填料比例显著相关，能够准确地反映堵塞程度.原位测量选择运行了1~5 a的4个潜流人工湿地（A、B、C、D湿地）进行，运行一段时间后，潜流人工湿地入口处、湿地管道破损处和使用时间较长的湿地堵塞系数较高，最高达0.998 km/d，而运行情况良好的D湿地堵塞系数在0.5 km/d以下.研究显示，原位测定结果能很好地反映湿地的堵塞情况. 

In-Situ Determination of Clogging Degree of Subsurface Flow Constructed Wetland

Constructed wetlands (CWs) are widely used in wastewater treatment due to their low operating costs and high treatment efficiency. However, clogging resulted from substrate materials would occur during the operation of subsurface flow constructed wetlands (SSFCWs), consequently resulting in the reduction of utilization efficiency and shortening the service life. Currently, there is a lack of effective methods and instruments for in-situ determination of the degrees of clogging in SSFCWs. In this study, an in-situ method based on the permeability coefficient was established to evaluate the degrees of clogging in laboratory- and field-scale SSFCWs. Furthermore, an instrument for in-situ measurement of the degree of clogging of SSFCWs was developed in conjunction with pressure detection and data processing modules, and its feasibility was also examined in laboratory- and field-scale SSFCWs using different substrate materials including sand and gravel. The results showed that the clogging coefficients were 0.69, 0.84 and 0.91 km/d when the ratios of sand to gravel were 2:1, 4:1, and 8:1, respectively. The measured clogging coefficients were significantly correlated to the ratios of sand to gravel, indicating that the clogging degrees can be accurately reflected by the clogging coefficients. In-situ measurements of clogging coefficients were performed in four SSFCWs which have been operated for 1 to 5 years. The clogging coefficients of the SSFCW entrance, surrounding areas of damaged wet pipe and long-operated SSFCWs could reach up to 0.998 km/d, which was higher than those of the un-clogged D CW was under 0.5 km/d. Therefore, the proposed method and the developed instrument can be well applied to evaluate the clogging degrees of SSFCWs.